高速离心压缩机旋转失速的全流场数值模拟

使用商业计算流体动力学(Computational fluid dynamics,CFD)计算软件CFX求解三维雷诺平均的Navier-Stokes方程组,结合出口气腔模型对某带无叶扩压器的离心压缩机的旋转失速现象进行数值模拟。为了准确地模拟小流量下的失速流动现象,在CFD计算中采用包括蜗壳在内的全场网格。首先使用定常计算得到该离心压缩机的稳态性能曲线,并和试验测量值进行比较。然后引入出口气腔模型,模拟离心压缩机内的旋转失速流动。在小流量下模拟得到离心压缩机内部流场的非定常流动现象。分析气腔模型不同参数对失速流动的影响,气腔体积越大,计算得到的失速频率越低。

Numerical Simulation of Rotating Stall inside High Speed Centrifugal Compressor Using Entire Geometry Mesh

Numerical simulation results ofrotating stall flow phenomenon inside a centrifugal compressor with vaneless diffuser by solving three-dimensional Reynolds averaged compressible N-S equations using commercial computational fluid dynamics(CFD)sottware CFX adopting RNG k-εturbulence model are presented.For exactly simulating the rotating stall at small flow rate,the whOle flow field mesh including volute is used.Firstly the steady performance curve is obtained using steady calculations and comparing with experimental results.Secondly,an air chamber model is added at the volute outlet to simulate the rotating stall flow phenomenon inside the centrifugal compressor.The centrifugal compressor internal flow fields at different times during the stall cvcle at the small mass flow rate are given to observe the stall flow phenomenon.The air chamber influence on the rotating stall is also investigated.The simulation indicates the more the plenum chamber volume is,the lower the stall frequency will be.